All my break ups were people leaving me, so I'm not sure I have any real experience to share
I regret the pain I caused for sure but looking back with the hindsight of 20-25 years my relationships then broke up for a lot of other reasons too - not just alcohol or drugs.
I'm sure that some couples do get back together when one of them enters recovery, but a lot don't - and I wouldn't like to give you false hope.....
What I can say is I wouldn't be with my current partner or living the current life I lead (which I love) without those breakups - and this relationship is the best of my life.
Maybe that's just around the corner for you too Fiona?
D